Got A Flat? Get A New Tube With The Correct Valve - Bicycle inner tubes (the tube is what's inside the tire), use one of two types of valves for inflation: Schrader or Presta. Schrader valves are an exact match with the valves on car tires. They have a spring-loaded valve mechanism inside. (If this mechanism leaks or fails it can be tightened or replaced easily and for very little cost.) Presta valves seal with air pressure. They're lighter and have fewer parts so there's less to go wrong. (This type of valve can be finicky if it gets muddy or clogged with tire sealant.) Presta valves are smaller in diameter than Schraders, so they fit in rim holes made for either type. Schrader valves only fit in rim holes designed for their larger diameter. When buying a pump, be sure it will fit the valve type you have. Most today fit both valves or can easily be converted, but check to make sure.